Content identification systems for various media types, such as audio or video, use many different methods. A client device may capture a media sample recording of a media stream (such as radio), and may then perform a search in a database of media recordings (also known as media tracks) for a match to identify the media stream. The sample recording could be preprocessed on the client device to extract relevant features for content identification. The sample recording may be passed to a content identification module, which can perform content identification of the sample and return a result of the identification to the client device. A recognition result may then be displayed to a user on the client device or used for various follow-on services, such as purchasing or referencing related information. Other applications for content identification include broadcast monitoring or content-sensitive advertising, for example.
In example content identification systems, the content identification may be concluded after a result is returned to the client device. Some content identification systems, however, may have low discriminability, which may result in a number of false positive matches. In addition, some content identification systems may not disambiguate between multiple possible matching recordings in the database. For example, if the sample recording spans a segment shared by multiple target recordings in the database, the content identification system may determine that any of these multiple recordings is a match. This situation could arise if there are multiple versions of a media recording, such as for example, a radio mix, an extended dance mix, or a mash-up, in which segments from the same original recording are sampled into different works. In these example cases, a result of a content identification may be incorrect.